3 phase calculation review

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paul hodge

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Location
atl
I have 9- 208 volt, 2520 watt, single phase loads. I calculate 15120 kva per phase. My question to the forum is the calculation of amps per phase. When connecting loads to 3 phase,208 volt panel. Will 15120?208=amps per phase or 15120?208?1.73=amps
 

GoldDigger

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Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Try to use unambiguous terms.
The loads you list will be wired between two ungrounded conductors (line to line).
The current in one of those loads could arguably be called current on one phase.
What you are looking for is the current in each line, also arguably the current in each phase.
In any case, the current on each of the three lines is 22680 divided by 208, divided by 3 and then multiplied by 1.73 to deal with the vector addition.


Tapatalk!
 
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Pharon

Senior Member
Location
MA
How are you getting 15,120 kVA per phase?

9 x 2,520 watts = 22,680 watts

What's the power factor of these loads?

The amps per phase is based on the full load power (VA) divided by the voltage. If it's 3 phase, you also divide by 1.73.

Ex.

Single Phase: 20,000VA/208V = 96A/phase

3 Phase: 20,000VA/(208 x 1.73) = 56A/phase
 
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bob

Senior Member
Location
Alabama
I have 9- 208 volt, 2520 watt, single phase loads. I calculate 15120 kva per phase. My question to the forum is the calculation of amps per phase. When connecting loads to 3 phase,208 volt panel. Will 15120?208=amps per phase or 15120?208?1.73=amps

No. You calculate 9 x 2520 watts = 22680 watts. Not per phase. You have 3 sets of 3 x 2520 watts = 7560 watts. You can connect 7560 watts between AB,AC and BC. If so, you can calculate the load as 3 phase load. 22680/(208 x 1.73) = 63 amps.
 
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